The gastrointestinal tract in adult humans is about 7-9 meters in total. Presently, of these 7-9 meters only as much as about 1.2 meters, extending from the ends of the gastrointestinal (GI) tract inwardly, may be imaged in commonly practiced medical imaging techniques (colonoscopy). Usually such imaging techniques involve inserting a tubular optical device (such as fiber optics) into the upper digestive system through the mouth (gastroscopy) or into the colon through the anus (colonoscopy) and advancing it along the gastrointestinal tract to inspect it and detect the presence of pathologies.
It may take years for a colon polyp to grow and turn malignant. In the absence of neurological warning system to indicate the occurrence of malignancies in their early stages it is often that the diagnosis of gastrointestinal malignancies is too late to be cured. Problems in the GI tract are ever too often detected only when they appear in great gravity and even then detection is made possible through the discovery of secondary indications (such as fecal occult blood occurrence). Early detection can be a major factor in improving the patient's chances of survival.
Some of the commonly occurring GI diseases include GI internal bleeding, inflammations of the GI tract, polyps, tapering of the GI tract, intestinal perforation, arteriovenous malformation. Internal bleeding may be caused by ulcer or varicose veins. These diseases cannot be detected in X-ray imaging or other non-invasive imaging methods until they evolve to traumatic proportion, yet even when diagnosed it is difficult to point out their exact location if that happens to fall beyond the inspectable range.
GI tract cancers are considered major factor in older adults fatalities. Gastrointestinal malignancies are considered to be the 2nd highest factor in male fatalities, and 3rd highest factor in female fatalities. GI diseases may be classified with reference to their location in the GI tract and the distribution of these diseases was found to be as follows: 30 per cent occurring in the esophagus, stomach and duodenum, 10 per cent occurring in the small intestine and some 60 percent occurring in the large intestine.
The inability to image the small intestine may bring about the need to perform investigative abdomen incision, sometimes just for ruling out a vague suspicion of malignancy.
Although some 80 per cent of the GI diseases may supposedly be detected by colonoscopy or gastroscopy, sometimes these invasive techniques may be considered undesired. These techniques are relatively costly, requiring the presence of a several member medical team throughout the procedure. Furthermore it is statistically shown that about one in 2000 patients is prone to perforation of the GI tract caused by a sharp object (the imaging tool) during the performance of the procedure. Such an incident immediately requires surgical intervention.
U.S. Pat. No. 5,604,531 (Iddan et al.) entitled IN-VIVO VIDEO CAMERA SYSTEM, filed in 1995, and incorporated herein by reference, discloses an in-vivo video camera system and an autonomous video endoscope The system includes a swallable capsule, a transmitter and a reception system. The swallable capsule includes a camera system and an optical system for imaging an area of interest onto the camera system. The transmitter transmits the output of the video camera system and the reception system receives the transmitted video output.
U.S. Pat. No. 4,278,077 (Mitzumoto) entitled MEDICAL CAMERA SYSTEM, filed in 1979, and incorporated herein by reference, discloses a capsule-shaped miniature camera comprising at least one permanent magnet, an induction coil, a lamp serially connected to the induction coil and a shutter device. The induction coil induces an electromotive force when a magnetic field generated by electromagnets outside the camera acts on it. The electromotive force turns on the lamp and drives the shutter device.
The video camera system of the '531 patent (Iddan) employs analog video and analog transmission. It is evident that it provides an image focused at a predetermined fixed distance from the optical lens and consequently, due to the poor lighting conditions within the GI tract, blurred image of objects falling outside or falling short of the focal range. As the GI tract is composed of parts of different diameters (the esophagus, stomach, small and large intestines) it is anticipated that substantial information will be omitted or severely degraded in the image obtained by Iddan's system. Furthermore the inside walls of the GI tract are also present “hilly” topography, and therefore pose difficulties to the imaging abilities of that system.
It is noted that these prior art optical imaging devices are limited in their field of view as they include a single optical system and are therefore limited to one directional view. For irregular surfaces as exist in the GI tract this may result in many hidden areas that the imager will not view properly. Furthermore the possibility of the capsule flopping over or turning around is real and may hamper with the proper functionality of the device.